Adjustable cutter for boring-bars and the like.



T. E. PATTINSON. ADJUSTABLE cuTTERfoR oRlNG BARS AND. 1HE UKE.

APPLlCATlON FILED DEVC. 16. 1913.

Patented May18,'1915 @MWL Wz'wes' 6,51:

1HE NoRRls PETER: ca., wAsHlNsrcN, u. cv

WALTHAMSTOW, LONDON, ENGLAND, ASSIGNOR 0F ONE-HALF TO CHARLES FLETCHER LUMB, OF LONDON, ENGLAND.

THOMAS EDWARD PATTIN SON, 0F

ADJUSTABLE CUTTER FOR BORING-BARS AND THE LIKE.

nimeer.

Specification for Design.

Patented May i8, 19315.

Application led December 16, 1913. Serial No. 806,956.

To all wit-0m t may concern.'

Be it known that I, THOMAS EDWARD PAT- TINsoN, a subject of the kKing of Great Britain, residing in Walthamstow, London, England, have invented certain new and useful Improvements in Adjustable Cutters for Boring-Bars and the like, of which the following is a specification.

This invention relates to double ended cutters for use with engineers boring bars. As hitherto constructed when cutters of this class become worn it is necessary in order to restore them to their full length that they should be heated and then drawn out to the desired extent. This method of procedure occupies considerable time in view of the numerous operations involved, and further necessitates the retempering of the tool.

The present invention has for its object to produce a double ended cutter for a boring bar which cutter is so constructed that the necessary elongation thereof may be effected without the aid of heat. With a cutter according to the present invention, moreover, provision may be made whereby the degree of the expansion may be controlled so that cutters of predetermined length may be readily produced.

A. cutter according to the present invention comprises two hard steel cutting bodies which are connected by a piece or length of some metal which is of a sulfiiciently ductile character to elongate under pressure, which pressure may conveniently be produced by hammering.

In order to produce cutters of any predetermined length, the cutter is placed in a frame or box, the distance between the end walls of which is equal to the desired length of the cutter. The yielding metal center is then hammered until further elongation is checked by the end walls of said frame or box.

In order that the invention may be the better understood, drawings are appended in which Figure l. is a side elevation of a cutter constructed in accordance with this invention. Fig. 2. is a plan. Fig. 3. is a side elevation showing the cutter with the'eXpansible metal center omitted. Fig. 4:. is a plan of the parts shown in Fig. 3. Fig. 5. is a side view partly in section showing the tool for expanding the center of the cutter in position. Fig. 6. is a side elevation showing a cutter after repeatedly eXpanding the center portion. Fig. 7. is an elevation partly in section showing the cutter in the boX for limiting the expansion of the center portion and with the tool in position ready to eX- pand the center. Fig. 8. is a plan showing the tool in the box ready for the application of the eXpansible center portion. Fig. 9. is a side elevation of the parts shown in Fig. 8. Fig. l0. is a plan showing the cutter in position in the boring bar. Fig. ll. is a side View of the tool employed to effect the expansion of the center part of the cutter. s

Referring to the accompanying drawings, a and findicate the respective cutting ends of the tool and which ends as shown are provided at c with cutting edges. The parts a and as shown in the drawings are recessed at al b1, such recess forming a key to retain the ends of the eXpansible metal center portion (Z. The opposite edges of the center portion d are preferably of angular outline, for example, V shaped, as shown at a2 2 Figs. l, 5, 6, 7, and 9.

While I do not desire to limit myself to any precise method of assembling the parts of the cutter,` from my own experience I nd in practice that this may most conveniently and rapidly be effected with the aid of the device shown in Figs. 8. and 9. In the figures referred to, there is shown a trough or boX comprising a bottom e1 side walls e2 and an end wall e3. Formed at suitable distances apart along the bottom e1 of the boX are holes c4 adapted to receive pegs Figs. 8 and 9, formed at the lower end of a plate e5 which plate is of substantially the same width as the space between the side walls e2. The parts a and b are placed in position in the box, the part a being placed with its outer end in contact with the end wall of the boX, while the outer end of the part b abuts against the plate Fig. 9. Molten metal is then poured in until the space left between the inner ends of parts a and b is illed as also the recesses al and b1 in said parts. The space between the side walls of the box is substantially equal tothe width of the cutter. It will be understood that the parts a and fore being placed in by the molten metal.

While I do not desire to limit myself in any way to the employment of any part-icular metal or alloy of metals for the center position and connected Z) will be tempered beico part of thecutter, that it is .preferable to use a quick cooling metal, such for example, as hard tinmans solder. The surfaces contacting with the solder are first tinned to secure proper cohesion of the solder with the tool.

Obviously instead o f solder as above described, I may employ any metal which as compared with the end a nature such that it will, when hammered or otherwise subjected to-pressure, be caused to elongate. Thus, for example, I may form the part d of brass, copper, iron, mild stee l Instead of melting the metal, the center portion may be fitted to the Vends a and b and secured therein by expanding the lparts engaging the recesses-ct1 b1. f

There are other methods of attaching the center part d to parts a and b which will readily be apparent to those skilled in the art and which consequently need not be here further specified. l

When it is desired to elongate the cutter, the soft center portion CZ is subjected t0 pressure which may most conveniently be effected by hammering the same. In order that the hammer blows may be more effective, I prefer to employ a device such as f shown in elevation in Fig. 11 and which device is preferably formed of round metal and is of substantially U shaped outline. In use the limbs of thedevice are` caused t0 straddle the center d and the cutter is placed upon some hard surface when the upper member of device e is hammered, the pressure thus applied causing the part d to expand. j The extent to which the expansio-n of part cl may be carried is limited only yby the thickness ofv said part d. In Fig.v6. I have illustrated the appearance of a cutter after repeatedexpansion of the part Z which it will be noted is reduced from its original thickness to a narrow web all in which condition the cutter is still'serviceable, as the repeated hammering has hardened the part l1 so that it is still sufficiently strong for se. l

As will be readily understood, it is desirable in some cases that the expansion ofthe center` part .d shall be controlled as upon the one hand it is difficult toregulate the force of the blows of the hammerzso that the desired expansion is not exceeded, while upon the other hand, it is troublesome to repeatedly examine the cutter by means of calipers'or other gage in order to see when the cutter reaches the desired length. In order, there- Copies of this patent may be obtained for I have found in prac-tice` parts L and bis of Y V f. The part ive cents each, by

Washington; D. C.

fore,.to overcome the difliculties above stated,

I employ a vbox or frame such as shownvin Fig. 7 land which is provided with sidewalls g,`ends g1' and a bottom g2. Thedistance betweentheends glis Vequal to the extreme overall dimensions of the cutter. The bottom of the box as also the upper edges of the side wallsdare recessed as shownvat g3 to permit'the'application of the aforesaid body el under the blows of the hammer. will expand until the ends of the cutter press against the ends g1 of the box when further 'elongation of thecutter will be prevented.

In Fig. 10. the cutter isfshown as in position'in the boring bar, indicated by h, and which is=provided with a slot which, while being of substantially the same depth as the height Vor thickness of the cutter is of somewhat greater Width one side a sufficient space to permit the introduction of a spring h1 or any other suitable device. It willbe noted that the bar is of sufficientdiameter to prevent either of so that there is left upon the ends of'thesoftmetal center d'being exposed so that no strain falls upon this portion. The position of the spring h1 is upon the side of the cutter facing the direction of the feed which in Fig. 10 is shown by the arrow z.

Claims:

1. A double ended cutter for a boring bar 'comprising two cutting members and an intermediate member of softer extensibles." of the cutmetal attached at each end to one ting members. f

2. A double endedy cutter for avv boring bar, comprising two cutting members of hard Steel, any intermediate member of softer metal, 'rejections' on the ends of said intermediate member engaging said recessesV in the ends of the cutting members. Y Y

3. A double ended cutter for a boring bar,

the ends thereof being recessed,

comprising two cutting members of hard "f steel, the endsthereof being recessed,afn intermediate member of solder, projections upon the ends of said intermediate member engaging said recesses in the ends of ting members. Y n

In witness whereof I have hereunto signed my name in the presence of the two undersigned witnesses. i

Y 'Tiicms EDWARD rirriNlsoN.

Witnesses:

E. E. GRIFFIN, W. Knock.

addressing the Commissioner of Patents,

the cut- 

